Síntesis y caracterización electroquímica de una membrana de poli(5Afen) para el desarrollo de electrodos modificados útiles para la determinación de neurotransmisores en presencia de ácido ascórbico

En este trabajo de tesis doctoral se presenta la síntesis de la membrana de un polímero conductor, la poli(5-amino-1,10-fenantrolina), mediante la electropolimerización del monómero usando métodos potenciodinámicos y potenciostáticos sobre diferentes sustratos. La síntesis se caracterizó voltamperométricamente y se estudió el depósito de la membrana con los modelos que describen la formación de nuevas fases electroquímicas, mediante el análisis de los transitorios potenciostáticos de corriente. Se estudio la respuesta del electrodo modificado a la variación del pH, así como el comportamiento electroquímico de adrenalina y el ácido ascórbico en presencia de la membrana polimérica. El electrodo modificado se optimizó para obtener la mejor respuesta en presencia de adrenalina, en función de los parámetros de síntesis de la membrana. Así mismo, se empleó para determinar el punto de equivalencia en titulaciones potenciométricas ácido-base. Además, su empleo como sensor para la determinación voltamperométrica de adrenalina y dopamina, en presencia de ácido ascórbico. Validando el sensor para la determinación analítica de adrenalina y se utilizó para la determinación en un preparado farmacéutico.The present work shows that the 5-amino-1,10-phenanthroline (5Aphen) molecule can be electrochemically polymerised, forming a conducting polymer, through potentiodynamic as well as potentiostatic methods onto different electrode substrates: 1) A composito electrode formed by with carbon paste in an epoxy matrix, 2) glassy carbon and 3) polycrystalline gold. Further. From the analysis of the experimental potentiostatic current-time j-t plots obtained using electrodes 2) and 3) it is shown that for both cases the formation mechanism of the polymer, (Poly5Afen) involves the simultaneous presence of an adsorption process, which seems predominant at times short enough to the start of the potential jump, and a three-dimensional 3D nucleation and growth process limited by the monomer diffusion toward the electrode’s interphase. The mechanism suggests that the growth of the polymer takes place via direct incorporation of the monomer species. Studies carried out varying the angular speed of the number a vitreous carbon 2) rotating disc electrode (RDE) showed that the limiting current increased directly proportional to the square root of the rotation frequency, as predicted by the Levich equation, thus indicating that the possible formation of intermediate oligomer species have a small effect on the polymer growth. It has been recognized that the synthesis method to produce conducting polymers plays a decisive role, because important features of the resulting membrane clearly depend on it. Variation of the membrane’s features such as the thickness, morphology and chemical properties will influence the overall response towards a given analyte present in solution. This work presents the results concerning the voltamperometric response generated during the oxidation of adrenaline using Pulse Differential Voltammetry, PDV, in the system composed by 0.1 M NaCl | carbon paste electrode, CPE, modified with poly(5Aphen) surface membranes, generated through potentiostatic and potentiodynamic means in solutions containing ascorbic acid, AA The results indicate that the electrochemical process to generate the membrane permits to control its thickness, improves the range of signal separation and the response of the adrenaline

Hydrothermal Fabrication of Carbon-Supported Oxide-Derived Copper Heterostructures : A Robust Catalyst System for Enhanced Electro-Reduction of CO2 to C2H4

Anthropogenic CO can be converted to alternative fuels and value-added products by electrocatalytic routes. Copper-based catalysts are found to be the star materials for obtaining longer-chain carbon compounds beyond 2e products. Herein, we report a facile hydrothermal fabrication of a highly robust electrocatalyst: in-situ grown heterostructures of plate-like CuO−CuO on carbon black. Simultaneous synthesis of copper-carbon catalysts with varied amounts of copper was conducted to determine the optimum blend. It is observed that the optimum ratio and structure have aided in achieving the state of art faradaic efficiency for ethylene >45 % at −1.6 V vs. RHE at industrially relevant high current densities over 160 to 200 mA ⋅ cm. It is understood that the in-situ modification of CuO to CuO during the electrolysis is the driving force for the highly selective conversion of CO to ethylene through the *CO intermediates at the onset potentials followed by C−C coupling. The excellent distribution of Cu-based platelets on the carbon structure enables rapid electron transfer and enhanced catalytic efficiency. It is inferred that choosing the right composition of the catalyst by tuning the catalyst layer over the gas diffusion electrode can substantially affect the product selectivity and promote reaching the potential industrial scale

A MOF-Based Spatial-Separation Layer to Enable a Uniform Favorable Microenvironment for Electrochemical CO2 Reduction

Regulating the local microenvironment of active sites to increase their specific CO2 concentration and pH gradient, is a promising approach to optimize the electrochemical CO2 reduction reaction (eCO2RR). However, currently reported morphological strategies display an uncertainty to the compatibility and distribution between catalytic sites and their microenvironment. Here, a uniform spatial-separation metal-organic framework (MOF) layer between active sites and bulk electrolyte is proposed, which enables each active site to locate in a similarly favorable microenvironment. Zinc oxide (ZnO) nanorods (NR), a representative electrocatalyst for eCO2RR, is covered with a Zeolitic imidazolate framework-8 (ZIF-8) thin layer to serve as a model system. The prepared ZnO NR@ZIF-8 exhibits an enhanced Faradaic efficiency toward CO at a wide range of potentials and reaches a maximum FE of CO (85%) at −1.05 V versus reversible hydrogen electrode, which is one of the best records till date. Moreover, the hydrophobic ZIF-8 layer protects ZnO against self-reduction. Such performance benefits from the porous ZIF-8 shell with high CO2 affinity, realizing efficient CO2 access and retaining an increased local pH near ZnO active sites

Flexible and Binder-Free Iron Phosphide Electrodes Using a Three-Dimensional Support for High Hydrogen Productivity

In this work, an inexpensive and reliable microstructured electrode for the hydrogen evolution reaction (HER) is developed. This cathode is made of Earth-abundant elements consisting of iron phosphide as an electrocatalyst and carbon felt (CF) as a flexible conductive scaffold. Its porous character and binder-free FeP coverage over the carbon fibers generate a high number of accessible active sites for the reaction, achieving a high value of the electrochemically active surface area. The electrode reaches 100 mA ⋅ cm by applying only −53 mV vs RHE at 50 °C in 0.5 M HSO, demonstrating excellent electrocatalytic activity for the HER and outstanding stability in acidic electrolyte. Furthermore, the feasibility of these electrodes for industrial application is evaluated using a PEM electrolyzer. The developed prototype with a cathodic area of 1.8 cm shows a very promising performance, reaching 14.9 mmol H ⋅ h ⋅ cm (corresponding to 800 mA ⋅ cm) at a voltage of only 2.1 V

Propuesta de un índice de calidad de grasas (ICG)

This paper presents the concept of the fat quality index (FQI), which is based and established in pursuancet of the current food regulations. It is a numerical value representing the correlated information of all parameters that provide the definition of fat according to the international guidelines. With the implementation of this index, it is possible to compare different types of fats using a single numerical value, which facilitates the elucidation of the effects of treatment processes or origins of fats. The FQI includes all the parameters considered in the regulations by incorporating a sub-index for each parameter and using the minimum and maximum limit values to model and adjust an equation describing the quality of fat according to the standard. Finally, the procedure is used to obtain indices based on other experimental works that assessed the quality of fat samples produced under different operating conditions, treatment, origin or processes, allowing for better comparison and evaluation. Therefore, this index is an excellent analytical tool for assessing the quality of fats from different origins for human consumption.En este artículo se presenta el concepto de índice de calidad de una grasa (ICG), que se basa y se establece en virtud de los reglamentos alimentarios actuales. Es un valor numérico que representa la información correlacionada de todos los parámetros que proporcionan la definición de la grasa de acuerdo con las directrices internacionales. Con la implementación de este índice es posible comparar los diferentes tipos de grasas usando un único valor numérico, lo que facilita la elucidación de los efectos de los procesos de tratamiento u orígenes de las grasas. El ICG incluye todos los parámetros considerados en la normativa mediante la incorporación de un sub-índice para cada parámetro y utilizando el valor límite máximo y mínimo para componer y ajustar una ecuación que describe la calidad de la grasa de acuerdo con la norma. Por último, el procedimiento se utiliza para obtener los índices en base a otros trabajos experimentales que evaluaron la calidad de las muestras de las grasas producidas bajo diferentes condiciones operacionales, tratamientos, orígenes o procesos, permitiendo una mejor comparación y evaluación. Por lo tanto, este índice es una herramienta analítica excelente para evaluar la calidad de las grasas de diferentes orígenes para el consumo humano

Nursing approach

Introduction: Complex wounds require advanced techniques for their management and care. Wound care costs are high, so healthcare professionals need to be aware of available therapies. Negative pressure therapy is a technology for which more and more data on its effectiveness in complex wounds are being collected. Objective: The objectives of this review were to analyze if the application of negative pressure therapy in complex wounds is effective; to compare the effectiveness of negative pressure therapy with other conventional treatments, as well as its combination with other therapies; and to evaluate the quality of life of patients undergoing negative pressure therapy and collect their main characteristics. Methodology: A bibliographic review focused on articles published between November 2015 and June 2022 was carried out. The following databases were consulted: PubMed (Medline), Google Scholar, Web of Science (WOS), Scielo and Scopus. Results: The most used pressures in the studies coincide at −125 mmHg and in the range of −125 mmHg to −150 mmHg. In the pediatric population, pressure levels vary by age group. A pressure of −75 to −125 mmHg is recommended for children over 12 years of age, and −50 to −75 mmHg is recommended for children under 2 years of age. Conclusions: Negative pressure therapy stands out for its rapid rate of granulation, the prevention and effective treatment of infections, the variety and malleability of dressings, its various applications and the possibility of using it with other therapies to accelerate wound closure

New Method of Production and Characterization of Haemozo-in and Β-Haemozoin from Meccus longipennis

Background: Understanding the significance of hemozoin (Hz) in the process through which Plasmodium is released from the heme group in the food vacuole during hemoglobin degradation, will allow the development of more effective drugs against malaria. Therefore, the development of methodologies to obtain Hz synthetically will facilitate an in vitro evaluation of new anti-malarial drugs. Methods: We present a methodology with good results to obtain Hz from fecal material of blood-sucking insects Meccus longipennis. The preparation of biological cultures of the parasite (Plasmodium) transmitter of the disease is not necessary. Results: The hemozoin molecule and its dimer were obtained using the method described and it was possible to validate a comparison with the positive and negative controls using different analytical techniques. Conclusion: The proposed method allows obtaining hemozoin and its dimer demonstrating equivalence with positive controls that demonstrate that the present procedure may be an alternative for the evaluation of antimalarial drugs

Temas Socio-Jurídicos. Volumen 6 No. 19 Marzo 1988

De gran importancia para el desarrollo en la práctica, de los objetivos de modernización de la administración de justicia en nuestro departamento, el convenio suscrito por el instituto ser de Investigación Cámara de Comercio de Bucaramanga Universidad Autónoma de Bucaramanga, en el curso del evento, permitirá dotar al Tribunal Superior de Distrito Judicial de Bucaramanga, de los elementos tecnológicos de la computación y los programas informáticos, que le permitan impartir justicia, rápida, oportuna y eficaz. Presentamos los documentos que recogen la convergencia de voluntades de las entidades comprometidas, así como la intervención del Ministro de Justicia, testigo del acuerdo.Of great importance for the practical development of the objectives of modernizing the administration of justice in our department, the agreement signed by the Bucaramanga Chamber of Commerce Research Institute-Bucaramanga Autonomous University, during the event, It will allow equipping the Superior Court of the Judicial District of Bucaramanga with the technological elements of computing and computer programs that allow it to impart justice quickly, timely and efficiently. We present the documents that collect the convergence of wills of the entities involved, as well as the intervention of the Minister of Justice, witness of the agreement

Facing seawater splitting challenges by regeneration with Ni−Mo−Fe bifunctional electrocatalyst for hydrogen and oxygen evolution

Altres ajuts: ICN2 is funded by the CERCA Programme/Generalitat de Catalunya. X.G. is grateful to Generalitat de Catalunya for PhD grant 2017 FI_B 00137. JL is a Serra Húnter fellow and is grateful to ICREA Academia program.Hydrogen, produced by water splitting, has been proposed as one of the main green energy vectors of the future if produced from renewable energy sources. However, to substitute fossil fuels, large amounts of pure water are necessary, scarce in many world regions. In this work, we fabricate efficient and earth-abundant electrodes, study the challenges of using real seawater, and propose an electrode regeneration method to face undesired salt deposition. Ni−Mo−Fe trimetallic electrocatalyst is deposited on non-expensive graphitic carbon felts both for hydrogen (HER) and oxygen evolution reactions (OER) in seawater and alkaline seawater. Cl pitting and the chlorine oxidation reaction are suppressed on these substrates and alkalinized electrolyte. Precipitations on the electrodes, mainly CaCO, originating from seawater-dissolved components have been studied, and a simple regeneration technique is proposed to rapidly dissolve undesired deposited CaCO in acidified seawater. Under alkaline conditions, Ni−Mo−Fe-based catalyst is found to reconfigure, under cathodic bias, into Ni−Mo−Fe alloy with a cubic crystalline structure and Ni : Fe(OH) redeposits whereas, under anodic bias, it is transformed into a follicular Ni:FeOOH structure. High productivities over 300 mA cm and voltages down to 1.59 V@10 mA cm for the overall water splitting reaction have been shown, and electrodes are found stable for over 24 h without decay in alkaline seawater conditions and with energy efficiency higher than 61.5 % which makes seawater splitting promising and economically feasible